Comparative study of the vicinal functionalization of olefins with 2:1 bromide/bromate and iodide/iodate reagents
作者:Manoj K. Agrawal、Subbarayappa Adimurthy、Bishwajit Ganguly、Pushpito K. Ghosh
DOI:10.1016/j.tet.2009.01.095
日期:2009.4
halohydrins, halo methyl ethers, and halo acetates from olefins using 2:1 Br−/BrO3− and I−/IO3− reagents. In many cases both reagents afforded products selectively in high yields. The highest halogen atom efficiencies attained were 97% and 93% for Br−/BrO3− and I−/IO3−, respectively. Of the two reagents, I−/IO3− was established to be the preferred reagent for vicinal functionalization of linear alkenes and
NaIO<sub>4</sub>-Mediated Selective Oxidative Halogenation of Alkenes and Aromatics Using Alkali Metal Halides
作者:Gajanan K. Dewkar、Srinivasarao V. Narina、Arumugam Sudalai
DOI:10.1021/ol0358206
日期:2003.11.1
[reaction: see text] NaIO(4) oxidizes alkali metal halides efficiently in aqueous medium to halogenate alkenes and aromatics and produce the corresponding halo derivatives in excellent regio and stereoselectivity. The system also demonstrates the asymmetric version of bromo hydroxylation using beta-cyclodextrin complexes, resulting in moderate ee.
Tribromoisocyanuric Acid: A New Reagent for Regioselective Cobromination of Alkenes
作者:Pierre Esteves、Marcio de Mattos、Leonardo de Almeida
DOI:10.1055/s-2006-941601
日期:2006.6
A simple one-step method for the preparation of tribromoisocyanuric acid in good yield (87%) has been developed. The reaction of tribromoisocyanuric acid with alkenes in presence of nucleophilic solvents (MeOH, i-PrOH, AcOH and a mixture of H2O-acetone, 1:5) led to the corresponding β-bromoethers, β-bromoacetates and bromohydrins, in high regioselectivity and good yields (73-98%).
Surface polarity of cetyltrimethylammonium bromide (CTAB) aqueous micelles was checked by use of as a probe the bromination reaction of a series of 1-alkenes and a water-soluble alkene, cis-4-cyclohexene-1,2-dicarboxylic acid dimethyl ester (I). There was strong inhibition (10(5)-10(6)-fold) of the second-order reaction rate constants relative to those in water; moreover, both kinetics and the product distributions suggested that alkenes had different locations at the micellar surface. Kinetics in the presence of added NaBr and n-decane supported this location hypothesis.